CVE-2001-1242 in Un-CGI
Summary
by MITRE
Directory traversal vulnerability in Un-CGI 1.9 and earlier allows remote attackers to execute arbitrary code via a .. (dot dot) in an HTML form.
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Analysis
by VulDB Data Team • 05/31/2018
The vulnerability described in CVE-2001-1242 represents a critical directory traversal flaw affecting Un-CGI version 1.9 and earlier implementations. This security weakness resides in the web application's handling of user input within HTML forms, specifically when processing directory navigation sequences. The vulnerability enables malicious actors to manipulate file system access by injecting .. (dot dot) sequences into form parameters, thereby bypassing intended security restrictions.
This directory traversal vulnerability operates by exploiting improper input validation mechanisms within the Un-CGI application framework. When user-supplied data containing directory traversal sequences is processed without adequate sanitization, the application fails to properly restrict access to files and directories outside the intended web root. The flaw essentially allows attackers to navigate upward through the directory structure and access restricted files or execute code on the affected system.
The operational impact of this vulnerability extends beyond simple information disclosure to encompass full system compromise capabilities. Remote attackers can leverage this weakness to execute arbitrary code on the target system, potentially gaining complete control over the affected server. This represents a severe privilege escalation vulnerability that can lead to data breaches, system infiltration, and further lateral movement within network environments. The vulnerability affects web applications built on the Un-CGI framework, making it particularly concerning for organizations relying on this technology stack.
From a technical perspective, this vulnerability aligns with CWE-22 Directory Traversal and follows patterns commonly associated with path traversal attacks. The flaw demonstrates the critical importance of input validation and proper sanitization of user-supplied data before processing. The ATT&CK framework categorizes this as a privilege escalation technique through path traversal, where adversaries manipulate application logic to access restricted resources. The vulnerability's exploitation typically involves crafting malicious form submissions containing sequences like ../../../etc/passwd or similar directory traversal patterns that bypass normal access controls.
Effective mitigation strategies for this vulnerability include implementing comprehensive input validation mechanisms that reject or sanitize directory traversal sequences in all user-supplied data. Organizations should upgrade to Un-CGI versions that address this vulnerability, as the original affected versions lack proper security controls. Additional protective measures involve implementing proper access controls, restricting file system permissions, and employing web application firewalls that can detect and block suspicious traversal patterns. Regular security audits and code reviews focusing on input validation practices help prevent similar vulnerabilities from emerging in future implementations.